Ictal Electroencephalographic Findings in Children with Migraine Headache.

Objectives
In this study, the EEG findings in children with migraine headache were assessed in Bahrami Hospital, Tehran, Iran from 2014 to 2016.


Materials & Methods
In this observational cross-sectional study, 71 consecutive children with migraine headache were enrolled. The EEG findings were determined and compared with other variables.


Results
There were 25 cases (35.2%) with abnormal EEG and the type of EEG abnormality comprised slow waves and sharp waves in 19(68%) and 8(32%) patients, respectively.


Conclusion
Nearly one-third of children with migraine might have abnormal EEG.


Introduction
Migraine headache is a common somatic pain leading to numerous problems in patients due to high frequency and recurrence (1). These are most common type of headache especially leading to seeking a physician by patients due to intermittent course (1). This would result in decreased quality of life due to mental and somatic problems (2).
For this matter prompt definite diagnosis and treatment is crucial (3).
More severe migraine headache would result in more decrease in quality of life (4).
Headache is also an important neurological problem in children seen in 26% of 12 to 13-yr-old and 31% of 14 to 15-yr-old subjects (5). Migraine headaches may be seen in 3 to 10 percent of children (6,7). Diagnostic procedures are important for both diagnosis of migraine and rule out of other differential diagnoses (5-7). In migrainous patients, low excitation threshold in the region of occipital cortex may trigger epileptic seizure (8). Occipital lobe epilepsy is an important differential diagnosis of migraine headache (9).

For this matter, electroencephalography (EEG)
is an important diagnostic tool used for roll out of probable epilepsies (10). The rate of EEG abnormalities is reported from 5.4% of migraine without aura to 43.5% in children suffering from migraine with aura.
There are little investigations on the electroencephalogram findings during the headache attacks of migraines. Hence in this study, the EEG findings in children with migraine headache were assessed. The frequency of migraine headache was 5 times, 5 to 10 times, and more than 10 times in 47.9%, 43.7%, and 8.5%, respectively. The mean initiation age was 6.9 ± 1.9 year. Fifty-two patients (73.2%) had positive family history of migraine.

Discussion
In this study, the electroencephalographic findings in children with migraine headache were assessed and 35.2% had abnormal EEG as slow and sharp waves. Spike or spike waves were not seen in any of the patients. Occipital and temporo-occipital were most affected zones. Male gender and some relieving factors were contributing to EEG abnormality.
In Iran, 20% of children with migraine had abnormal EEG and the type of migraine was related to EEG abnormality (10). However, there was no association in our study. Four children with basilar migraine were assessed which all had abnormal EEG as delta and theta waves (11). However, in our study basilar migraine was not seen but the slow waves constituted the majority of abnormal EEG.
EEG should be performed in children with basilar migraine or those with prolonged aura or suspected seizure (12). However, the epilepsies and aura were not related to abnormality of EEG in our study.
Twelve percent of migraine children had abnormal EEG (13). The abnormality was more common in those with shorter headache. Besides, in our study, there was no significant association. Moreover, the abnormality rate was higher.
The best time for EEG recording is at the time of a headache and during asymptomatic intervals, the diagnostic value was decreased (14). This matter explains the cause of difference in results of studies. The most diagnostic value of EEG was reported in complicated cases (15). This matter is not in congruence with our study. Hemiplegic migraine children were assessed and reported that EEG had good diagnostic value in these cases (16

Acknowledgment
We are grateful to Research Deputy of Tehran University of Medical Sciences to fund this research. All authors agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.